16.  If people keep polluting the ocean, no creature there will survive _____.

A. at all cost                        B. fora long while

C. in the long run                 D. by no means

17.  Mr. Wilson is a man of patience and kindness, and his good temper never _____him.

A. fails                  B. disappoints               C. controls            D. worries

18.  —Did Jim come?

—I don't know. He ______ while I was out.

A. might have come                    B. might come

C. must have come                     D. should have come

19.  —I prefer a computer made in your company, but I may need some more information about the product.

—_______.

A. Thank you                             B. Its a pleasure

C. You are welcome                    D. At your service

20.  —Would you mind moving over a little? I have to pass here.

—______. I’d like to help.

A. Not in the slightest                         B. Don't mention it

C. Never mind                                   D. At your service

21.  This was returned because the person ______ this letter was addressed had diedthree years ago.

A. to whom           B. to which            C. which        D. whom